Zipper Noise and Graphics

[Music Manic]

I've been testing the noise from my Pulsar 2 anlogue outs today.

Ok I've got 2 monitors plus a Geforce 7300 SE.
One is set to VGA the other is DVI.
It seems that the VGA ONE is much noisier but when I change the resolution it also decreases the noise on some settings..

This is all at the highest gain on my Headphone amp.

Wasn't the zipper bug fixed in the latest Scope version 5 or is it just a video prob?

Thanks

[the19thbear]

Its a video/computer problem. it has nothing to do with scope.

First: find another screen to test with. Some older screens radiate noise into the soundcard.

If that doesn't work:
One solution would be to make sure that NONE of your audio thingies, and I mean NONE share ground with your computer. or make sure that they ALL share the same ground as the computer.
It's kind of a time consuming thing to do, but:
I imagine you have many different audio gizmos plugged in to various different power sockets in your wall.. Right?
Not all Sockets have the same ground and that can cause problems.

Start out by ONLY turning on the computer and the headphone amp and leave all other things unplugged from any socket in the wall. ALL. Connect your scope cards outputs directly to your headphone amp. Is there any noise? If there is, Connect the computer or headphone amp to another power outlet in the wall. Try until it works. Then one by one, connect your other stuff untill you hear the noise again. When you find the culprit, cut the ground on the audio cable on that device and somehow connect it with the ground on your computer/headphone amp.. Or just leave it unconnected, but make sure you put duct tape on the end of the cable..This has helped me many times.

[jksuperstar]

A trick many laptop performers use is to lift the ground to the computer. You can do that by clipping the ground off the power cable, or use one of those old 3-prong to 2-prong adapters. This helps remove the ground loop.

Or, if you can use only ADAT out of the scope cards, as bear said, keep the audio on it's own common power rail, and nothing will go across the optical cables.

[Music Manic]

Hi Guys,

Yes it's definitely the Video card.

Got rid of all the noise (analogue hiss of Pulsar outs is natural I guess) except the Zipper noise.
I'm not sure if I should get a dual DVI card. Gary, any recommendations? I have the Nvidia Geforce 7300SE so I though it would make much noise?

Would moving the cards further away from the Graphics card help? Is there any way I could shield the Graphics card, or is that too much?

I have no noise in the headphone amp except that damn zipper noise, even when Scope isn't running.

I was wondering if it's still a version 5 bug like Gary use to say.

Thank you so much for your help and wisdom guys. Appreciated!

[astroman]

just googled the video-card...
I'd say get rid of it asap... 64MB, fairly slow and sharing with main memory (probably, unless tweaked...)
The latter may be the source of your trouble - I never had any graphcard that transmitted through air.
They rather pick the way through powerlines and slot-interface.
Recently bought a Gforce 8400GS for 25 Euro (brandnew).
Btw it's the 2nd number that counts in performance, NOT the first one. As I was taught by my PC reseller... I don't mind that stuff much... no games but Scope here.
You may try to set the card to use only it's 64MB onboard Ram.
To check the 'pure' analog signal, disconnect everything from the IO-Plate and plug headphones into the analog out.
The opamps are driven a bit hard but it won't do no harm to the trusty 5532s. If you have 600 Ohm cans they even can drive them properly.

cheers, Tom

[Music Manic]

just googled the video-card...
I'd say get rid of it asap... 64MB, fairly slow and sharing with main memory (probably, unless tweaked...)
The latter may be the source of your trouble - I never had any graphcard that transmitted through air.
They rather pick the way through powerlines and slot-interface.
Recently bought a Gforce 8400GS for 25 Euro (brandnew).
Btw it's the 2nd number that counts in performance, NOT the first one. As I was taught by my PC reseller... I don't mind that stuff much... no games but Scope here.
You may try to set the card to use only it's 64MB onboard Ram.
To check the 'pure' analog signal, disconnect everything from the IO-Plate and plug headphones into the analog out.
The opamps are driven a bit hard but it won't do no harm to the trusty 5532s. If you have 600 Ohm cans they even can drive them properly.

cheers, Tom

Wow! Only 64 Megs. I didn't realise that I've become a dinosaur.

There are many brands of 8400GS cards Tom.Are they all the same? Which one should I go for?

http://www.google.co.uk/search?sourceid ... 24&bih=649

This one looks good and it even has HDMI:

http://www.ebay.co.uk/itm/GEFORCE-8400G ... 2844wt_992


I also wanted to ask you about your Telfunken power supply also. I would like to get a nice clean power supply for my computer setup.
I also need to ask you a few questions about my setup. I will PM you my email if that's ok.

You sound like an electronics expert!

Many thanks

James

[astroman]

imo any at that price will do, it's just branding - they are probably all from the same factory lines...
64 MB is perfectly ok for a 2-D display. The problem would be the allocation of motherboard Ram to extend the card's memory... (which they most likely activate by default)
reads familiar ?
it's exactly what Scope is doing with reverbs and what causes the PCI bandwidth trouble

I've mentioned that Telefunken PSU already somewhere, mostly as an example how crappy most gear is constructed today.
It weighs a ton... or rather 10 pounds.
The (analog) regulation has a dedicated supply for it's own power from the main transformer.
So the control unit is totally independent from the stabilized load. It has sensing and switching lines to activate a reserve unit, in case the main device breaks - and cost a fortune when new...
Minimal traces of AC at the outs are compensated by a negative feedback loop to phase it out, so no more than 0.1 mV of pollution.
To be honest it's (almost) overkill in all domains... but just 100 Euro on eBay
A good power supply can be a major factor of cost for the manufacturer, and it's usually overlooked completely.
Unfortunately those devices are barely usable with anything other that they were originally built for.
It's a 24V 4A unit, asymmetric, constructed to supply broadcast console modules.

cheers, Tom

[Neutron]

I found out a couple of years ago that the circuit in my breaker box which feeds my studio had no ground at all, not good! so i fixed it (just the ground wire not properly on the ground bus in the box, fortunately). after that everything that was not optical or digital become more noisy and hummy, i managed to figure it all out but it was a bit of a surprise.

now its nice and quiet, actually sometimes i think almost too quiet, if i forget to turn the volume down!